Baseball or softball bat

ABSTRACT

A sweet spot  3  of an impact portion  2  has a smaller diameter than the other portions of the impact portion  2,  whereby the impact portion  2  has an intermediate tapering shape in the longitudinal direction. Thus, even if hit with a portion at some distance from the sweet spot, rebound performance is not significantly reduced. Therefore, a bat having a large sweet area and capable of reducing the occurrence of foul balls is obtained.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an improvement of a baseball orsoftball bat hereinafter referred to as a bat). The present inventionprovides a high-performance bat having a large sweet area that canachieve a good slugging distance even when a ball is hit with a portionother than a sweet spot, by forming the outer shape of the impactportion of the bat to have an intermediate tapering portion or recessedportion in the longitudinal direction.

[0003] 2. Description of the Background Art

[0004] The greater diameter of an impact portion tends to provide asmaller stiffness for elliptic deformation and hence give higher reboundperformance to a ball. Then, it is generally known that a bat whichgives excellent rebound performance can be effectively designed bymaking the diameter of an impact portion as large as possible.

[0005] On the other hand, if the diameter of the impact portion is toolarge, the bat becomes too heavy for a hitter to take a comfortableswing. If such a large diameter is to be maintained with less weight,sufficient strength is not obtained.

[0006] Then, to give improved rebound performance to the conventionalbat, it has been necessary to reduce the impact portion in length sothat the diameter of the impact portion is made large with less weight.As such, the conventional bat has a small sweet area.

[0007] As shown in FIG. 4, the conventional bat has an impact portionhaving a perimeter of a linear or gentle convex curve in thelongitudinal direction. Thus, if a right-handed batter hits a ratheroutside ball with the impact portion near a leading edge, the stroke mayresult in a foul ball on the first base side.

[0008] On the other hand, if a right-handed batter hits a rather insideball with the impact portion near a grip end, the stroke may result in afoul ball on the third base side.

SUMMARY OF THE INVENTION

[0009] Therefore, the present invention aims at providing a bat whichhas such a large sweet area that a certain level of rebound performanceis ensured even if a ball is hit with a portion at some distance from asweet spot, and which may reduce the occurrence of foul balls.

[0010] The baseball or softball bat of the present invention includes animpact portion which has a smaller diameter at a sweet spot than at theother locations of the impact portion, and which has a recessed externalshape in the longitudinal direction.

[0011] The outline of a recessed part of the impact portion may be acurve, straight line, arc, or ellipse. The perimeter of the recessedpart has a curvature radius of 200-1000 cm.

[0012] Preferably, the diameter of the impact portion increases from thesweet spot toward the leading edge and grip end of the bat.

[0013] The foregoing and other objects, features, aspects and advantagesof the present invention will become more apparent from the followingdetailed description of the present invention when taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a plan view of a bat according to the present invention.

[0015]FIG. 2 is a plan view of a bat according to another embodiment ofthe present invention.

[0016]FIG. 3 is a graph showing a comparison result of reboundperformance between the bat of the present invention and theconventional bat.

[0017]FIG. 4 is a plan view of the conventional bat.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Now, the embodiment of the present invention will be described.

[0019] Referring to FIG. 1, a bat 1 of the present invention has asmaller diameter at a sweet spot 3 of an impact portion 2 that gives themaximum bounce to a ball than at the other locations of impact portion2. Impact portion 2 has a recessed outer shape. More specifically,impact portion 2 has a perimeter of an intermediate tapering shape inthe longitudinal direction.

[0020] The recessed shape is obtained with the diameter of impactportion 2 being minimum at the location of sweet spot 3 and graduallyincreasing toward a leading edge 4 and a grip end 5 of bat 1. Thus, evenif hit with the portion other than sweet spot 3, bat 1 has a large sweetarea and exhibits less reduction in rebound performance because of thelarger diameters of impact portion 2.

[0021] The outline of the recessed portion is desirably part of a curve,and especially an arc or ellipse with a curvature radius of 200-1000 cm.However, it may be part of a straight line as shown in FIG. 2.

[0022] Bat 1 can be made of various materials including wood, metal,fiber reinforced plastic (FRP) and the like. Bat 1 of the presentinvention can be made of any material.

[0023] If made of wood, bat 1 is formed by turning, followed byreinforcement by resin injection or the like.

[0024] If made of metal, bat 1 is formed by the conventionalmanufacturing method and then processed to have a tapering impactportion 2 with use of a metal roller or the like.

[0025] If made of FRP, for example, bat 1 is formed to have a taperingimpact portion 2 with use of a mold having the corresponding shape.

[0026] Bat 1 does not necessarily have to be formed of a singlematerial, but may be formed of different materials. For example, atapering tubular member of FRP may be used for impact portion 2 of metalbat 1, or a tapering metal tubular member may be used for impact portion2 of FRP bat 1.

[0027] Table 1 and FIG. 3 show a comparison result of reboundperformance between baseball bat 1 of the present invention shown inFIG. 1 and conventional baseball bat 1 shown in FIG. 4. Presentinvention Conventional example Distance from Diameter Rebound DiameterRebound grip end (mm) (mm) Coefficient (mm) Coefficient L1 480 69.00.560 63.0 0.480 L2 580 64.5 0.585 63.0 0.560 L3 680 63.0 0.600 63.00.600 L4 780 64.5 0.580 63.0 0.550

[0028] As is apparent from the above result, sweet spot 3 (portion about680 mm from the grip end) exhibits the highest rebound (restitution)coefficient, and the rebound coefficient decreases as away from sweetspot 3.

[0029] Although conventional bat 1 exhibits a considerable decrease inrebound coefficient as away from sweet spot 3, bat 1 of the presentinvention exhibits only a slight decrease in rebound coefficient becauseof the increasing diameter of the impact portion, having a large sweetarea.

[0030] In the present invention, the diameter of the impact portion atthe sweet spot is minimum and then the diameter gradually increasestoward the leading edge and grip end of the bat. Thus, if hit with theportion other than the sweet spot, the decrease in rebound performanceis not considerable because of the increasing diameter of the impactportion. As such, the bat has a large sweet area.

[0031] Further, the intermediate tapering shape of the impact portionhelps the ball hit with the end of the impact portion to be directed toa fair zone. Thus, the occurrence of foul balls and hence game lengthare reduced.

[0032] Although the present invention has been described and illustratedin detail, it is clearly understood that the same is by way ofillustration and example only and is not to be taken by way oflimitation, the spirit and scope of the present invention being limitedonly by the terms of the appended claims.

What is claimed is:
 1. A baseball or softball bat, wherein a sweet spotof an impact portion has a smaller diameter than other portions of saidimpact portion, and said impact portion has a recessed outer shape in alongitudinal direction.
 2. The baseball or softball bat according toclaim 1, wherein an outline of a recessed part of said impact portionincludes a curve.
 3. The baseball or softball bat according to claim 2,wherein the outline of the recessed part of said impact portion is partof an arc or ellipse.
 4. The baseball or softball bat according to claim3, wherein the outline of the recessed part has a curvature radius of200-1000 cm.
 5. The baseball or softball bat according to claim 1,wherein the diameter of said impact portion increases from said sweetspot toward a leading edge and grip end of said bat.
 6. The baseball orsoftball bat according to claim 1, wherein the outline of the recessedpart of said impact portion includes a straight line.